Marion Cotillard‘s career has taken her from commercial to indie, from mainstream American popcorn fare to the international arthouse. Yet the thought of working with Jean-Pierre and Luc Dardenne, brothers known for their poignant films about the life of underclass, seemed implausible when they approached her to star in “Two Days, One Night.”

“I didn’t even allow myself to dream about the Dardenne brothers, because I knew it would never happen,” Cotillard says in the 2015 Foreign Language issue of OscarWrap. “I couldn’t believe that they wanted to work with me, because of how different they usually work.”

Since her 2007 best actress Oscar for “La Vie En Rose,” Cotillard has played muse to Christopher Nolan, Woody Allen, Steven Soderbergh, Rob Marshalland Michael Mann, among many others. “I’m just lucky that I don’t have to try to maintain a career, because I get amazing opportunities from France, Belgium, England, America,” she told TheWrap.

The steady work has made her the biggest star to emerge from France in the last decade, so familiar to U.S. audiences that she landed a cameo in “Anchorman 2” —a sure sign that she was everything the Dardenne brothers should not be looking for.

But it was on the set of Jacques Audiard’s “Rust and Bone” that the Dardenne brothers, who serving as producers on that film, offered her the lead role in “Two Days, One Night.” Cotillard plays Sandra, a young mother forced to spend a weekend pleading with her co-workers to save her job by forgoing their bonuses.

The film, which was released in the U.S. by IFC, is one of the most acclaimed foreign-language films of the year, though it did not make the nine-film Oscar shortlist for the foreign category. (Cotillard is, however, eligible in the Best Actress category.)

“Maybe it is a little bit silly for us to cast her, because she is a big star,” said Jean-Pierre Dardenne. “But at the same time, we really felt she could bring the fragility and vulnerability that Sandra needed. We wanted to bring her into our family, and we felt she really had the traits that we wanted.”

But the Dardennes’ typically time-consuming rehearsal process, he added, was “a very big challenge for Marion, and a very big challenge for us as well. We wanted to see if she was able to do her role, but also see how the other actors that were not stars were able to play their roles, without having a distinction between them.”

During the rehearsals, Cotillard also spent time studying her character, who has missed work because of an unspecified breakdown and is fighting serious depression. “There was little information in the script about why was she depressed, how it affected her life and the lives of the people she loved, and where the state of depression comes from,” she said.

“So I had to create all this, and that was a very, very interesting part of the preparation. I needed to write down some scenes that I would use later to give her a memory of something, so she could break in tears out of nowhere.”

She didn’t discuss that research with her directors, but undertook it privately. And she didn’t get too clinical about it—in fact, she said, “the only research that I did was reading the Xanax label. I needed to know what were the effects of Xanax because I had never taken it before and I didn’t want to try to take a Xanax to see what it was.”

Instead, she said, she drew from personal experience to understand depression.

“I came, myself, very close to depression. It didn’t last long, because I have an ability to fight, and I’m a pretty good fighter. I fought with everything I could, because I didn’t want to fall in a deep state of depression,” Cotillard said.

“But because I came close, I could feel what it is to lose any sense of taste, to lose your energy, to lose your purpose. And so suddenly I could understand that it’s not that easy. It’s not just, you’re healthy, you’re alive, just move yourself. Sometimes you just cannot do it. So of course, those experiences helped me to understand Sandra and create her.”

The unabridged version of this story, “Marion Cotillard; What’s a Big Star Like Her Doing in a Place Like This?” appears in the 2015 Foreign Language issue of TheWrap’s Oscar magazine.

22 Biggest Snubs and Surprises: 2015 SAG Awards Nominations (Photos)

SNUB: Jessica Chastain failed to be recognized for her supporting role in "A Most Violent Year."

A24

SNUB: SAG voters also left off "A Most Violent Year" star Oscar Isaac from the Outstanding Performance by a Male Actor in a Leading Role list.

A24

SURPRISE: Naomi Watts earned a very unexpected nomination for her performance in "St. Vincent."

The Weinstein Company

SNUB: Critics continue to rave over David Oyelowo's turn in "Selma" as Martin Luther King Jr. His name was left off the list of SAG Award nominees however.

Paramount

SNUB: Carmen Ejogo's portrayal of Coretta Scott King in "Selma" was ignored by the Screen Actors Guild.

Paramount

SNUB: "Selma" received zero nominations across every category on Wednesday morning.

Paramount

SNUB: Nominated for an Actor last year, Kerry Washington was left off of the list this year for her role as Olivia Pope in "Scandal."

ABC

SURPRISE: Jennifer Aniston's performance in "Cake" had some saying this could be the role that would earn her some long-overdue recognition. SAG voters gave her the first major nom of what could be a busy award season.

Cinelou Films

SNUB: Steve Carell received a nomination for lead actor but "Foxcatcher" was shut out in the Best Cast category.

SNUB: "Unbroken" was shut out in all major categories, though the film did score a nod for Outstanding Action Performance by a Stunt Ensemble in a Motion Picture.

Universal Pictures

SNUB: Bradley Cooper's role in "American Sniper" failed to impress SAG voters enough to give him a nod.

Warner Bros.

SNUB: Neither of Marion Cotillard's performances in "Two Days, One Night" or "The Immigrant" were deemed worthy of a SAG Award nomination.

Cinéart

SNUB: Her role on "Masters of Sex" earned her an Emmy nomination but was ignored by SAG on Wednesday morning.

Showtime

SNUB: "Orange is the New Black" received a Comedy Ensemble nomination and co-star Uzo Aduba scored a nod for her role as Suzanne “Crazy Eyes” Warren. Taylor Schilling came up empty handed though.

Netflix

SNUB: In "Two and a Half Men's" final season, SAG failed to recognize Jon Cryer, who has only been nominated for a SAG Award once. Conversely, he's won two Emmys and been nominated seven times for playing Alan Harper on the CBS sitcom.

CBS

SNUB: She received an Emmy nomination in 2014 but Michelle Dockery failed to earn a SAG Award nomination for her role on "Downton Abbey."

PBS

SNUB: Another year without a SAG Award nod for Lena Dunham. The "Girls" star has yet to be nominated.

HBO

SNUB: Laura Dern was left off of the list of supporting actress nominees for her performance in "Wild."

Fox Searchlight Pictures

SNUB: Now in her fourth iteration of "American Horror Story," Jessica Lange was unable to secure a nomination for her role in "Freak Show."

FX

SNUB: After two straight SAG Award nominations, Jeff Daniels' name wasn't called on Wednesday morning. The HBO series, now in its final season, was snubbed in all categories.

HBO

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Jessica Chastain, Kerry Washington, Bradley Cooper and “Selma” make the list of unexpected inclusions and omissions

SNUB: Jessica Chastain failed to be recognized for her supporting role in "A Most Violent Year."